The Scottish Naturalist. 6$ 



of strong wire frames the size of the paper to be made use of in 

 drying the specimens. Over the frames lies a set of thin wires 

 about half an inch apart. The requisite pressure is obtained by 

 using a pair of rug straps ; and a little experience shows that the 

 pressure given by these is ample. These frames have very great 

 advantages over wooden boards in lightness, portability in travel- 

 ling, and freedom in giving off the moisture of the enclosed plants, 

 thereby rendering the changes of paper required less numerous, 

 while diminishing the risk of injury to the specimens. 



Some groups of plants require special precautions to ensure 

 successful results. Those growing submerged must not be ex- 

 posed long to the air, or they will wither and shrivel so as to make 

 it almost impossible to obtain a satisfactory specimen from them. 

 Species that have the submerged leaves much cut and the stems 

 very slender should be treated like seaweeds and be spread out 

 on the sheet to which they are to remain affixed under water, the 

 water being run carefully off after the plant has been properly 

 arranged on the paper. Of course all must be thoroughly washed 

 before being laid out. A piece of linen above the plant in the 

 press will prevent it from sticking to the dry paper, while it will 

 adhere readily to the sheet on which it is lying. 



Some fleshy plants e.g., Sedums and some Orchids, are very 

 troublesome because of the difficulty experienced in killing them, 

 and in the almost certainty of their leaves dropping off or turning 

 black in the press. It is known to most that such plants require 

 to be dipped into boiling water, ironed with a hot iron, or other- 

 wise subjected to treatment to kill them before being put into 

 the press. Some will stand an almost incredible amount of such 

 usage without being killed, and may even begin to grow again 

 after they are in the herbarium. 



The tendency in many flowers to become black, or otherwise 

 unsightly, is unfortunately known to every collector by unpleasant 

 personal experience ; and is especially common in blue flowers, 

 less frequent in red. Yellow flowers very generally stand drying 

 well, and change comparatively little. The best general precaution 

 is to dry them as quickly and as thoroughly as possible, using arti- 

 ficial heat for those peculiarly liable to suffer. It has been recom- 

 mended to cover the fresh flowers in a vessel with fine sand, and 

 then to expose them to heat for a time. Mr. English recommends 

 the use of dry plaster of Paris, heated to 90 or ioo° F. In this 

 they are left for 12 hours, or longer if necessary, then they are 

 removed, brushed with a camel's hair brush, and carefully washed 



